5,612 research outputs found
Internal Time Peculiarities as a Cause of Bifurcations Arising in Classical Trajectory Problem and Quantum Chaos Creation in Three-Body System
A new formulation of the theory of quantum mechanical multichannel scattering
for three-body collinear systems is proposed. It is shown, that in this simple
case the principle of quantum determinism in the general case breaks down and
we have a micro-irreversible quantum mechanics. The first principle
calculations of the quantum chaos (wave chaos) were pursued on the example of
an elementary chemical reaction Li+(FH)->(LiFH)*->(LiF)+H.Comment: 7 pages, 3 figures, accepted for publication in Int. J. of
Bifurcation & Chao
Exchange shift of stripe domains in antiferromagnetically coupled multilayers
Antiferromagnetically coupled multilayers with perpendicular anisotropy, as
[CoPt]/Ru, Co/Ir, Fe/Au, display ferromagnetic stripe phases as the ground
states. It is theoretically shown that the antiferromagnetic interlayer
exchange causes a relative shift of domains in adjacent layers. This ``exchange
shift'' is responsible for several recently observed effects: an anomalous
broadening of domain walls, the formation of so-called ``tiger-tail'' patterns,
and a ``mixed state'' of antiferromagnetic and ferromagnetic domains in
[CoPt]/Ru multilayers. The derived analitical relations between the values of
the shift and the strength of antiferromagnetic coupling provide an effective
method for a quantitative determination of the interlayer exchange
interactions.Comment: 4 pages, 3 figure
Chiral skyrmions in thin magnetic films: new objects for magnetic storage technologies?
Axisymmetric magnetic lines of nanometer sizes (chiral vortices or skyrmions)
have been predicted to exist in a large group of noncentrosymmetric crystals
more than two decades ago. Recently these magnetic textures have been directly
observed in nanolayers of cubic helimagnets and monolayers of magnetic metals.
We develop a micromagnetic theory of chiral skyrmions in thin magnetic layers
for magnetic materials with intrinsic and induced chirality. Such particle-like
and stable micromagnetic objects can exist in broad ranges of applied magnetic
fields including zero field. Chiral skyrmions can be used as a new type of
highly mobile nanoscale data carriers
Chiral Skyrmionic matter in non-centrosymmetric magnets
Axisymmetric magnetic strings with a fixed sense of rotation and nanometer
sizes (chiral magnetic vortices or Skyrmions) have been predicted to exist in a
large group of non-centrosymmetric crystals more than two decades ago. Recently
these extraordinary magnetic states have been directly observed in thin layers
of cubic helimagnet (Fe,Co)Si. In this report we apply our earlier theoretical
findings to review main properties of chiral Skyrmions, to elucidate their
physical nature, and to analyse these recent experimental results on
magnetic-field-driven evolution of Skyrmions and helicoids in chiral
helimagnets.Comment: 13 pages, 7 figures, invited talk - JEMS-2010 ( 23-28 August, Krakow,
Poland
New Perturbation Theory for Nonstationary Anharmonic Oscillator
The new perturbation theory for the problem of nonstationary anharmonic
oscillator with polynomial nonstationary perturbation is proposed. As a zero
order approximation the exact wave function of harmonic oscillator with
variable frequency in external field is used. Based on some intrinsic
properties of unperturbed wave function the variational-iterational method is
proposed, that make it possible to correct both the amplitude and the phase of
wave function. As an application the first order correction are proposed both
for wave function and S-matrix elements for asymmetric perturbation potential
of type The transition amplitude
''ground state - ground state'' is analyzed in detail
depending on perturbation parameter (including strong coupling
region ) and one-dimensional refraction coefficient .Comment: LaTeX, 13 page
Magnetic Fluctuations and Correlations in MnSi - Evidence for a Skyrmion Spin Liquid Phase
We present a comprehensive analysis of high resolution neutron scattering
data involving Neutron Spin Echo spectroscopy and Spherical Polarimetry which
confirm the first order nature of the helical transition and reveal the
existence of a new spin liquid skyrmion phase. Similar to the blue phases of
liquid crystals this phase appears in a very narrow temperature range between
the low temperature helical and the high temperature paramagnetic phases.Comment: 11 pages, 16 figure
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